Synthesis of green-to-red-emitting Cu-Ga-S/ZnS core/shell quantum dots for application in white light-emitting diodes

The Cu-Ga-S/ZnS quantum dots (QDs) emitting green-to-red light are successfully synthesized by the conventional hot-injection method. In the preparation process, 1-dodecanethiol (DDT) is not only used as the solvent but also the sulfur precursor and ligand. Therefore, all reactants are additives, which can reduce solution contamination. The peak wavelength of Cu-Ga-S/ZnS QDs' emission can be tuned from 520 to 619 nm by changing Cu/Ga stoichiometry. And these quantum dots have narrow full-width at half maximum wavelength of about 75 nm. Furthermore, a white quantum-dot-based light-emitting diode is obtained by depositing the yellow Cu-Ga-S QDs on a blue InGaN chip.